diff --git a/mini-lsm-mvcc/src/iterators/merge_iterator.rs b/mini-lsm-mvcc/src/iterators/merge_iterator.rs
index c4abc8d..b1f5bdf 100644
--- a/mini-lsm-mvcc/src/iterators/merge_iterator.rs
+++ b/mini-lsm-mvcc/src/iterators/merge_iterator.rs
@@ -37,7 +37,7 @@ impl<I: StorageIterator> Ord for HeapWrapper<I> {
 }
 
 /// Merge multiple iterators of the same type. If the same key occurs multiple times in some
-/// iterators, perfer the one with smaller index.
+/// iterators, prefer the one with smaller index.
 pub struct MergeIterator<I: StorageIterator> {
     iters: BinaryHeap<HeapWrapper<I>>,
     current: Option<HeapWrapper<I>>,
diff --git a/mini-lsm-starter/src/iterators/merge_iterator.rs b/mini-lsm-starter/src/iterators/merge_iterator.rs
index 04eca06..c4fae54 100644
--- a/mini-lsm-starter/src/iterators/merge_iterator.rs
+++ b/mini-lsm-starter/src/iterators/merge_iterator.rs
@@ -39,7 +39,7 @@ impl<I: StorageIterator> Ord for HeapWrapper<I> {
 }
 
 /// Merge multiple iterators of the same type. If the same key occurs multiple times in some
-/// iterators, perfer the one with smaller index.
+/// iterators, prefer the one with smaller index.
 pub struct MergeIterator<I: StorageIterator> {
     iters: BinaryHeap<HeapWrapper<I>>,
     current: Option<HeapWrapper<I>>,
diff --git a/mini-lsm/src/iterators/merge_iterator.rs b/mini-lsm/src/iterators/merge_iterator.rs
index c4abc8d..b1f5bdf 100644
--- a/mini-lsm/src/iterators/merge_iterator.rs
+++ b/mini-lsm/src/iterators/merge_iterator.rs
@@ -37,7 +37,7 @@ impl<I: StorageIterator> Ord for HeapWrapper<I> {
 }
 
 /// Merge multiple iterators of the same type. If the same key occurs multiple times in some
-/// iterators, perfer the one with smaller index.
+/// iterators, prefer the one with smaller index.
 pub struct MergeIterator<I: StorageIterator> {
     iters: BinaryHeap<HeapWrapper<I>>,
     current: Option<HeapWrapper<I>>,